[Brenck]

Hi Guys,

I have this time relay board witch is the FRM01 ( FRM01 Timer Relay Module by WardElder - Thingiverse ) conected to the mains ( 120vac ) of a switching power supply, this power supply is a 12vdc 10A output switching power supply. It provides the 12vdc for 2 brushed motor diaphragm pumps. So the relay board turns on SWPS witch then will turn on the pumps.

Problem is that the relay keeps getting stuck on the ''ON'' or NC state.... I tried to use it either on the NC or NO states and like invert the timing schedule on the but it doesn't matter, it will stick ON anyways. The only way to make it unstick is to tap the electrical box that the board is installed.

Searching on the web I've found that is due to relay welding its contacts...

I really don't know how to I make this stop happening, I tried to replace the relay on the timer circuit with another brand but it keeps happening over and over, I've tried to replace the timer board as well, 5 of them, it still happens. The current that my power supply consume is way less then the relay rating...

I'm desperate... Already burned 6 pumps due to the fact that they can't stay on for a long period of time, just short intervals. Sometimes I would just come back and see that is too late, pumps have burnt already...

I can't stand this happening anymore =... (

Is there something quick to do?

Thanks in advance to anyone who can help

[john-100]

the inrush current as you connect the mains supply to the switchmode power supply will be about 45A

I would use the timers relay either to control a solid state relay or a contactor to switch the 12V PSU mains supply ON & OFF

25A SSR data
Attachment 351262


12V contactor data
Attachment 351276

LP1SK0600JD | TeSys SK LP1S 2 Pole Contactor,

12 A, 12 V dc Coil | Schneider Electric

thats assuming you have the 12V version of the timer

otherwise a contactor with a 120V AC coil would be another option with the timers relay switching the 120V mains supply to a 120V contactor coil


John

[Jim Dawson]

Use the small relay to switch a larger relay that powers up the power supply. Sounds like the power supply inrush is too much for the small relay. Maybe install a PRD relay like this:

This is only an example http://www.newark.com/te-connectivit...25a/dp/33F1540